Weeks after it emerged that Boris Johnson was scrapping the annual gay pride mayoral reception at City Hall as part of wider cull of events for specific minority groups, it has been announced that the London mayor has decided to take part in tomorrow's gay pride celebrations.

The Conservative mayor will join thousands of revellers on the streets of central London to mark the contribution of gay people to life in the city.

Johnson raised eyebrows among some in the gay community when his deputy mayor, Richard Barnes, announced last month that the City Hall pride reception was being scrapped.

Instead, the mayor has scheduled a series of "borough community receptions" which will involve representatives from different minority and community groups by geographical area.

He believes the switch will bring people together rather than focusing on what is "different".

Johnson was not originally scheduled to make an appearance at the London gay pride celebrations, but has cleared his diary to help kick off proceedings when the parade begins.

His transport advisor, Kulveer Ranger, will be one of the speakers at the pride festival, in Trafalgar Square.

Johnson said today: "I am pleased to support our city's pride celebrations and proud of London's reputation as a place where you can be yourself.

"From poet laureates to politicians and pop stars to rugby players, there's an increasing confidence to be open about your sexuality.

"Nowhere is this more evident than in London, which is home to one of the largest lesbian, gay, bisexual and trans communities in the world.

"Everybody has the right to live their life as they wish, free from persecution and abuse, and my office is working with the community, the police and other partners to ensure that, irrespective of sexuality, all Londoners are able to participate fully in the life of the capital."

Johnson – once a staunch supporter of the controversial Section 28, the legislation introduced by the Conservatives in the 1980s to stop councils from "promoting" homosexuality – first made an appearance at London pride two years ago, wearing a pink stetson.

Lynne Featherstone, the Liberal Democrat equalities minister, and Nick Herbert, the openly gay Conservative policing minister, will also be in attendance.

However Theresa May, the home secretary, who also serves as the as minister for women and equality, will not be there.

David Cameron's decision to assign the equality brief to May, despite her voting record on gay rights, prompted a backlash from campaigners and a Facebook page calling for her to be sacked.

A spokesman for the equalities office said: "Whilst Theresa May will not be able to attend the pride parade due to a commitment to attend a freedom parade for British troops in her constituency, she wishes everyone at pride a fantastic day."